Hardiness: Zone 3.
Size: Massive Tree up to 65 ft tall.
Planting: Extremely tolerant, Full sun to part shade, can tolerate dry, windy, polluted, salted soils. Great for reclamation.
Fruit: Edible nut, up to 3cm.
Pollination: Self pollinating.
Use: Excellent for processing.
Ripening: Early to mid fall.
Pot: Bare root.
Bur oak acorns are not only the largest but also considered to be one of the mildest and best tasting acorns, though the tannins should still ideally be leached out before consumption.
Bur Oak is native to the eastern and central United States from the north down to Texas and Canada from the Maritimes to the prairies. It is a long lived tree capable of reaching 400 years old in the best of conditions. It can grow to up to 35 or 40 metres tall with equally large spreads but will tend to grow smaller the further north it goes in its planting range. The bark is light grey/brown with deep ridges and furrows. Leaves are dark green and glossy; significantly wider at the end and tapering towards the base. Bur Oaks produce the largest acorns of all the oaks, they can be 1.5 inches long with an oblong form and ½ to ¾ covered by a burr-like cup that gives the tree its common name.
Bur Oak is also the most widely spread of the oak species thanks to its ability to thrive in such a wide range of environmental conditions. It tolerates all soil types from wide pH ranges to all different compositions and its long taproot allows it to withstand long periods of drought. It grows best in full sun but is relatively tolerant of shade in its youth. It is one of the most fire tolerant trees due to the thickness of its bark and even when top killed by fire will sprout back vigorously from the base.
Bur Oak is an outstanding shade tree and is ideal for urban plantation due to its tolerance of air pollution and salt. Its hardiness and long life make it a popular choice for shelterbelts. Its ability to thrive in poor soils also makes it a great choice for reclamation of degraded sites.N